Case reports of malformations associated with maternal diabetes: history and critique.

Several malformations and malformation complexes have been alleged to be associated with maternal type 1 diabetes mellitus: in particular, sacral dysplasia, caudal regression/sirenomelia, femoral dysplasia, and holoprosencephaly. For some of the malformations the claim rests on case material, and for others on theoretical considerations. The history and evolution of these ideas are presented.